The primary metabolite of cocaine is benzoyl ecognine (BE). A desirable method for detecting cocaine use is the extraction of BE from urine into an organic phase solvent and subsequent analysis by High Performance Liquid Chromatography (HPLC). The attempt to develop such a method is hindered by the extreme water solubility of BE, making extraction into an organic phase extremely difficult. The present study attempts to use an ion-pairing agent to bind with BE and form a large, organically soluble ion-pair. The ion pairing agent used was Reinecke Salt in a I% solution. An aqueous solution of 50 ug/mL BE was treated with the Reinecke Salt solution and then extracted with methylene chloride. Initial analysis of the extracted ion pair was performed by Ultraviolet-Visible (UV-VIS) spectrometry. The structure of BE is pH dependent; existing as a positively charged species in acid, a zwitterion in neutral solution, and a negatively charged species in base. The pH dependence of BE results in a pH dependent ion pairing reaction; an ideal pH of 8.5 was determined for the extraction. A concentration variant peak at 255 nm was discovered using UV-VIS spectrometry, however, the peak does not exhibit linear concentration dependence and so is not currently of practical use.
Summers '96, C.J., "Toward an Efficient Method of Detecting Cocaine Metabolite in Urine" (1996). Honors Projects. Paper 13.